GDB step into Dynamic linker(ld.so) code

Question

I wanted to step into the code of ld.so whenever it will be used in my normal c code. I am trying to code flow through GDB in the TUI mode where you can see both source code and assembly as you step over the code.

For this I also installed libc-dbg binutils-source package from ubuntu package manager. GDB can find the debug symbols for the ld.so itself and I can step at the instruction level that is using si but I cant step at the source level as GDB is not able to find the source for ld.so and shows NO Source Available.

How can I make GDB find the source for ld.so so that I can also see which line in the ld.so source is actually being executed.

I am using Ubuntu 12.10 64bit with GCC 4.8.2

Answer 1

If you've libc's source code available, you can add sources to gdb's source path with dir command: Source_Path

Edit: To debug libc related files (in a Ubuntu distro) you would need to:

1. Get libc's debug information by installing libc6-dbg packet.
2. Get libc's source code by enabling source repositories (by running software-sources and and checking "enable source code repositories") and running apt-get source libc6
3. Add libc's debug information into LD_LIBRARY_PATH: export LD_LIBRARY_PATH=/usr/lib/debug or LD_LIBRARY_PATH=/usr/lib/debug gdb <application>
4. Add full path to c file to gdb's source path, this is: dir directory_path_libc_source/stdio-common

Answer 2

Download the Glibc source and path the same with gdb before debugging. Check this ubuntu blog